Apparatus for heating street-pavements.



G. H. LUTZ.

APPARATUS FOR HEATING STREET PAVEMENTS.

APPLICATION FILED FEB. Il. 1916.

Patented May 23, 1916.

Glfviybneoo yGEORG-E H. LUTZ, OF CHIGAGO, ILLINOIS.

. .arraimrus ron HEATING STREET-Pavnmrs.

Specification of Letters Patent.

Patented May 23, 1916.

Application med Febipary 11, 191s. serial N o. 77,776.

To all whom t may concern.'

Be it known that I, .GEORGE H. LU'rz, a citizen of the United States,residing at Chicago, inthe county of Cook and State of Illinois, haveinvented 4certain new and useful Improvements in Apparatus for HeatingStreet-Pavements, of which the following is a specification.

This invention relates to an apparatus for continuously generating arelatively large body of heated air or equivalent heat-conveying medium,and discharging it in heating relation to a relatively large area ofstreet surface in the form of an evenly distributed sheath evenly heatedthroughout, so that the heat treatment of the surface over which theapparatus is a plied at any given time will be uniform t roughout itsarea.

The apparatus is especially designed for use in heating street pavementsas a preliminary s tep to removing the upper stratum of plastic pavingmaterial in the process of re-surfacing the street; or for heating thesurface of stone pavements to render it re-I ceptive of the binder thatis employed in the aplplicationof an asphalt surface to an eXisti gstreet-surface of stone. Apparatus heretofore employed for -these andsimilar purposes has been found objectionable for various reasonsApparatus in which the heating flame is applied directly to thesurfaceis objectionable, because of the liabilityA of burning thematerial treated, and when used in connection with a heat-modifyingmeans such as air inlets or blast-producing means, such apparatus hasbeen objectionable because of the unequal distribution of the heatingmedium overthe surface to be heated.

The present invention seeks to improve the known apparatus. for heatingstreet.

pavements by developing a `largevolume of i heating medium from a bodyofair and fuel introduced conjointly into a combustion .chamber underconditions which insure not only an effective blast from the deliveryend of the apparatus, with consequent suction of an ample volume of airand complete combustion of the fuel, but cause this combustion to takeplace at a point suiciently remote from the point of discharge, toinsurecomplete mixture of the air and products of combustion and uniformtempering of the resultant heat-conveying body before it reaches thedischarge flue, so that substantially the same heating efect isdeveloped throughout the area which the machine is adapted to cover.

In carrying out the invention, I employ an elongated combustion chamberhaving at one end a discharge flue provided with the usual distributingand confining hood which defines the area of treatment, and having atits opposite end, a large air intake flue extending for some distanceback from the combustion chamber and having concentrically associatedtherewith, at its receiving end, a blast producer or blower and a fuelinjector; these parts being arranged so thatl they not only bring in alarge body 0f air under a considerable momentum, but mingle with theincoming air, an yannular stratum of blast medium, preferably steamsubdivided into a number of jets, and a central jet of fuel mixture,preferably oil and steam.

The invention will be fully understood upon reference to theaccompanying drawing, in which Figure 1 is a vertical longitudinalsection of a typical form of apparatus embodying the several features ofthe invention, and Fig. 2 is a detail View of the combined blasting orair-injecting device and fuel feed jet.

1 represents a hood adapted to be superposed upon an area of streetsurface to be heated, in position which conines a heating medium inrelation to the surface, and

2 is a supply flue for such hood. In orderto deliver to the' fl'ue 2, ahighly fluid heatconveying medium under a sulicient blast' 'chamber 3having at its end remote from the flue 2, a combined blast-developingand fuel-feeding intake 4. The intake 4: is constructed with an openouter end 5, so that the main volume of Huid entering it is atmosphericair, but it'is equipped with an annular blast-inducing blower 6 in theform of a steam conduit having jet openings presented longitudinally ofthe intake 4: and connected through suitably valved pipe 7 with a sourceof steam supply; and a concentric fuel atomizer and injector 8 of anysuitable construction, such for instance as a fuel pipe 9 fed bysuitably valved pipe 10, surrounded by a spaced jacket 11 in injectorrelation thereto and fed by the valved steam pipe 12. The axialdimension of the intake 4 isl sulicient to insure mixing and ignition ofthe fuel in the air and blast-inducing medium, so that by the time theseelements reach the combustion chamber 3, combustion is proceedingviolently, and by the time the resultant mixture of heated air andproducts of combustion reach the Hue 2, combustion `has substantiallyceased and the elements are thoroughly mingled and tempered, so thatthey reach the hooded surface in the condition already referred to. Thecombustion chamber is preferably provided with a baiie wall 13; alsowith a Water jacket 14 provided with a steam dome 15 as an economicalsource of steam required for operating the apparatus.-

16 represents a connection through which to receive steam fr om anexternal source whenever it may be desired, as for instance when the.apparatus is being started up from a cold state.

apparatus constructedas above described not only obviates thediHiculties encountered with apparatuses heretofore constructed, but itaffords a simple and effective means of developing the continuous supplyof Huid medium required for heating surfaces. in work such as thatreferred to; the apparatus is at all times subject to convenientsupervision and regulation; the blast-inducing element 6, which hasproven a particular source of annoyance and loss of time when employedin the discharge Hue, is in its present relation not only wheretemporary stoppage of some of its jets does not adversely affect theuniformity of the discharged heating medium, but where its jets canreadily be reached for cleaning and where theblower as a whole can bereadily cleaned by opening a blow-0H' cock 17 at frequent intervalsWithout shutting down the apparatus. Moreover, this location of theblower at a point where it is protected i' rom the heat of the apparatuspermits the use of a very much more eiicient blower and greatly lessensthe .cost of maintaining the blowing element as compared with thelocation in the Hue 2, as heretofore proposed. The blast developed inthe present machine imparts such momentum to the incoming charge thatthe expansion due to the heat of combustion Hnds its relief only towardthe discharge end of the machine' and thus adds to the blast in thedesired direction.

I claim 1. An apparatus for heat treatment of the surface material ofroadways; said appa-v ratus comprising an air heating and conditioningchamber having at one end a discharge Hue and a distributing hood,1and,at its end remote from said discharge Hue, means for maintaining in saidchamber, a body of air at high temperature, under sufficient pressure toforcibly expel 'the air and insure strong impingement of the hot airagainst the street surface beneath the hood; said means comprising anair intake Hue freely open at its outer end to atmosphere, ajet-injector discharging inwardly into said intake Hue and inducingtherethrough a glingof the air and burning gases and being Y elongatedbetween the intake and discharge Hues sufliciently to insure completionof combustion of the fuel and delivery of the air'to the hood withoutHame.

2. An apparatus for heat treatmenti V'of roadways; said apparatuscomprising an air heating and conditioning chamber having at one end adischarge Hue and a .distributing hood, and, at its end remote from saiddischarge Hue, means for maintaining in said chamber, a body of air athigh temperature, under suflicient pressure to forcibly expel the airand insure strong impingement of the hot air against the street surfacebeneath the hood; said means comprising'an air intake Hue freely open atits. outer end to atmosphere, a steam jet injector discharging inwardlyinto said intake Hue and inducing therethrough a strong -blast of air, asteam generating chamber located in heat absorbing relation to the airconditioning chamber, and adapted to develop steam under pressure andsupply it to the steam injector; and a liquid fuel atomizer and fuelinjector also discharging inwardly into said intake Hue and maintainingin and delivering with said blast of air, burning gases sufficient todevelop, throughout the body of air, the temperature required; the airintake and discharge Hues being of considerably smaller section than theconditioning chamber; the intake Hue having the capacity under theaction of the blast to maintain an air supply largely in excess of thatrequired for combustion, and the conditioning chamber being constructedto insure mingling of 5 the air and burning gases and being` elongatedbetween the intake and discharge flues sufficiently to insure completionof combustion of the flie and delivery of the air to the hood Withoutame.

The foregoing specification signed at 10 lVashington, District ofolumbia, this 11th day of February, 1916. l

GEORGE H. LUTZ.

